On Friday afternoon, you might see some brightly colored tables spread out on San Francisco's Market Street. They'll be the first signs of a much bigger event happening in a few months. San Francisco is holding a contest to make its most heavily traveled street as innovative as the city itself.

It's filled with hustle and bustle and its fair share of urban grit.

"Market Street is the great civic back bone of our city," said Kay Cheng with the San Francisco Planning Department.

That's why the planning department wants to do something bold on the main thoroughfare. But they're not sure quite what. So they're asking the city's brightest designers to join them in a prototyping festival.

"Where we do something temporarily to see if it works," Cheng said.

Fifty teams came up with 50 ideas.

"The concept of our prototype is called Arena Play, and it's bas a 6-sided ping pong table," said Gensler Architects designer Justin Choy.

The designs have to be interactive -- something to draw people in.

"A gumball machine or something that would dispense ping pong balls," said one designer.

Each team gets $2,000 from the Knight Foundation, to build a prototype that'll stay up for three days in April.

"To have them all in the same place at the same time, putting their vision together to create one unique vision, that's what makes this amazing," said Kristy Hilands with Yerba Buena Center for the Arts.

Of all the blocks that are part of the festival, one between 6th and 7th streets is among the most talked about. Once a vibrant part of the city's theatre district, many now see it as giant hole that tears Market Street in half. Or you could see it as a blank canvas.

"This part of the city has been all but abandoned for a generation," said Jensen Architects founder Mark Jensen.

But what if the arts came back?

"Our proposal is called Showbox," said another designer.

An ultra-modern performance space, it could give folks a reason to stop and stay awhile.

"We call it Tigers on Market Street," said Nature in the City director Amber Hasselbring.

The western tiger swallowtail butterfly lives and breeds on Market Street. Decorative diversions would point your eyes toward the overhead nets where caterpillars are hatching, maybe with complimentary binoculars.

"Trying to get them to look up and have slow observant moments with nature in downtown," Hasselbring said.

There are no winners or losers in the three-day festival, but some prototypes could get sponsors and live on for years.